In a transportation system, it is necessary to limit the speed of the transportation vehicles over predetermined zones along the vehicle paths (e.g. around curves or at passenger stations). The speed must be limited according to a profile which is acceptable to the comfort of vehicle passengers and which is compatible with the operational objectives of the transportation system. An example of such a speed limiting control system is shown in U.S. Pat. No. 3,519,805.
Because different operational objectives of a transportation system demand different speed limiting profiles, the choice of speed limiting profile depends first on the objectives of the particular transportation system in which the vehicle is operating. For example, if the object of the transportation system is to maximize the energy dissipation capacity of the vehicles, a constant energy speed limiting profile would be required; whereas if the system objectives were to minimize starting and stopping time of the vehicles, a constant deceleration speed limiting profile would be required. In prior art transportation systems for controlling vehicle speed, it has been difficult to change the speed limiting profile to accord with a change in the systems operational objectives after a first set of objectives has been implemented.
Whatever speed limiting profile is demanded by the transportation system's objectives, this profile must be modified to comport with the comfort of the vehicle passengers. Although these modifications may occur over only a relatively small portion of the speed control zone and may be relatively small in magnitude, they are essential. In prior art systems, these modifications have been expensive and difficult to implement.